Pay for the upgrade. The only way to guarantee Air France will upgrade a ticket is paying for an upgrade. Upgrade the ticket beforehand through either a booking agent or by calling the airline directly and requesting an upgrade. The fees will vary depending on the specific flight.
Join Air France's frequent flyer program or membership program. According to BBC News, the most likely way to upgrade without paying is joining airline loyalty clubs.
Avoid traveling with large groups. Book the ticket separately if traveling with a group, or travel alone or with only one other person. Airlines may not upgrade passengers who are part of a large group, even if the passengers do not mind separating.
Dress respectably. Customers who are dressed in grubby clothing with holes or who look less pristine are less likely to get upgraded. Money Saving Expert points out that a suit is not necessary, but having a clean and well-dressed appearance helps in getting an upgrade.
Convert credits on a BlueBiz card or similar Air France frequent flyer card. Credits are given by Air France for frequent flyers like BlueBiz members. To upgrade the seat, the member must buy a ticket at full price and request the upgrade at a BlueBiz service desk at least five days before the flight departs.